1. Field of the Invention
The present invention relates generally to solar heat exchangers and more particularly to a solar heat exchanger which operates at below atmospheric pressure and achieves high efficiency at a low cost.
2. Description of the Prior Art
Solar heat exchangers absorb the sun's radiant energy and transfer it to a fluid flowing through the exchanger. Generally, solar heat exchangers are constructed of rigid panels utilizing metal pipes through which a fluid is pumped. These panels are both heavy and expensive to construct.
Solar heat exchangers may operate at either above atmospheric pressure or below atmospheric pressure. When a solar heat exchanger operates at above atmospheric pressure, the transfer fluid is pumped through the exchanger. On the other hand, a solar heat exchanger which operates at below atmospheric pressure has the transfer fluid drawn through the exchanger by suction. A solar heat exchanger which operates at below atmospheric pressure is described in U.S. Pat. 4,048,981 issued to James C. Hobbs.